Method for sealing cartons



4 Sheets-Sheet 1 R GUYER METHOD FOR SEALING CARTONS Nov. 30, 1948.

Flled Nov 9, 1944 Nov, 30, 1948. R. GUYER msmon FOR smnme muons 4 Sheets-Sheet 2 Filed Nov. 9, 1944 R. GUYER METHOD FOR SEALING CARTONS Nov. 30, 1948.

4 sheets-sheet 3 Filed Nov. 9, 1944 Q NM w% w% hm.

ww mww Nov. 30, 1948. R. GUYER METHOD FOR SEALING CARTONS 4 Sheets-Sheet 4 Filed Nov. 9/1944 mw ah. Q @Nl llll lll llllllllll QM v Patented Nov. 1%, 1948 Ni STATES PTENT OFFICE METHOD FOR SEALING CARTONS Reynolds Guyer, St. Paul, Minn, assignor to Waldorf Paper Products Company, St. Paul, Minn, a corporation of Minnesota Application November 9, 1944, Serial No. 562,717

16 Claims. '3,

My invention relates to an improvement in method for sealing cartons, wherein it is desired to produce a sift proof and liquid tight folding carton.

In my previous application Serial No. 500,497, filed August 30, 1943, which has matured into Patent No. 2,407,781,,1 described a carton'of a somewhat similar construction to that herein involved. The present invention, however, provides a method for automatically closing the ends of such a carton and of sealing the ends to prevent the escape of the contents.

An object of the present invention is to produce a sealed carton which is sift proof and liquid tight. In following this method I employ a, carton comprising four hingedly connected wall panels which may be opened up into tubular form. In order to prevent wicking two glue flaps are connected along the edges of the outermost panels. These glue flaps are sealed together and folded ninety degrees and one hundred eighty degrees respectively, and secured to the outside of the carton so that no raw edges are presented at the interior of the carton. The end structure of the carton comprises two end panels hingedly connected to opposite wall panels, each end panel having a sealing flap connected thereto. One of the end panels is connected to the upper edges of two adjacent side wall panels by bellows panels.

An object of the present invention is to provide a coating of thermo plastic material on the interior surfaces of the carton and to first partially seal each end of the carton by folding the bellows folds and the associated carton sidewalls outwardly. This action also folds one end panel across the open end of the carton so that the sealing flap thereon is superimposed upon a marginal portion of the opposite end panel. By applying heat and pressure to the bellows folds and to the sealing flap on the first mentioned end panel, the first step in the sealing of the carton end may be accomplished.

A feature of my invention resides in turning the bellows folds inwardly after these folds have been sealed to their associated side wall panels. As the bellows folds are turned inwardly one hundred eighty degrees to overlie the outer surface of one end panel, the stiff two ply folds act in knee action lever fashion on the material at the pin hole corners to crowd the material into these corners. Thus by producing double thickness triangular folds secured together by a slipproof bond therebetween and subsequently folding these triangular folds over the end panel overlying the end of the carton, the pin holes usually container.

2 occurring at opposite corners of the carton may be effectively sealed.

A further feature of the present method lies in the fact that during the infolding of the bellows folds thecarton material forms welts along the crease lines. The triangular folds bear down on the welts; thereby exerting great force exactly at the critical point, causing a very tight closure of thepin hole.

A further feature of the present invention lies in looking the triangular folds in infolded position by inturning the remaining end panels of the carton to overlie the triangular folds. This feature crowds the carton material into the pin hole corners and acts to further close these corners.

A feature of the present invention lies'in the fact that during the preparation vof the carton blank and its treatment during the setting up operation, the side panels are not bent morethan ninety degrees with respect to the side wall panel to which it is hingedly and integrally secured. During the sealing operation the side panels are turned outwardly to a, position ninety degrees with respect to the side panels and then the triangular folds are folded inwardly through an arc of one hundred eighty degrees to a position substantially ninety degrees with respect to the side wall panels.

A further feature of the present invention lies in the fact that any necessary pressure may be applied to seal the bellows panels to the adjacent side wall panels and to seal the sealing flap of one end panel to the surface of the opposite end panel. As the sealing operation takes placewhile the respective folds extend outwardly from the carton, pressure urging these members into sealed relation can not distort the carton.

'A further feature of the present invention resides in the fact that the sealing is accomplished between thermo plastically coated surfaces of the The bellows folds are folded against the adjacent side wall panels in such a way that the two inner coated surfaces are in contact. Similarly the inner coated surface of the sealing flapfof the first folded end panel contacts the coated surface of the other end panel, thus providing contact between two coated surfaces.

- vThese and other objects and novel features of my invention will be more clearly and fully set forth in the following specification and claims. In the drawings forming a part of my specifi cation 5 Figure 1 is an end elevational diagrammatic view showing the manner in which the carton Figure 6 is a view of the carton as furnished by the manufacturer. 1

Figure 7 illustrates the same carton in expanded position.

Figure 8 shows the carton after the initial sealing stage.

Figure 9 shows the next stage in the sealing operation.

Figure 10 shows a subsequent stage in the seal ing operation.

Figure 11 shows the carton bottom entirely sealed.

Figure 12 shows the first step in sealing the top of the carton.

Figure 13 shows the next stage in the sealing of the carton top.

Figure 14 shows the top sealing virtually completed.

Figure 15 is a perspective view of the package in entirely sealed form.

Figure 16 is a diagrammatic view of the carton blank.

The carton A is best seen in Figure 16 of the drawings. The blank forming the carton includes a side wall panel In, a front panel I l, a side wall panel l2, and a rear panel I3 connected together along parallel fold lines I4, l5, and IS. A sealing flap I1 is connected to the side panel 10 along the fold line l9 and an opposite sealing flap 20 is connected to the panel I 3 along the fold'line 2|.

Fold lines 22 and 23'define the upper and lower edges of the wall panels. A top end panel 24 and a bottom end panel 25 are hingedly connected to the rear panel IS. A sealing flap 26 is connected to the top end panel 24 along a fold line 21; parallel to the fold line 22. A similar sealing flap 29 is connected to the bottom end'panel 25 along a fold line 30 parallel to the fold line 23.

The front wall panel H is provided with top and bottom end panels 3| and 32 similar to the panels 24 and 25 and similarlyconnected along the fold lines 22 and 23. Sealing flaps 33and 34 are provided on the end panels 3| and 32 and are connected thereto along parallel fold. lines 35 and 36.

Triangular side wall panels 31 and38 areoon nected to the top and bottom edges of the side panel I0 and similar triangular panels and 4| are foldably connected to the top and bottom edges of the side panel [2. The panels 3! and 39 are foldably and integrally connected to the end panels 3| and 32 by means of gusset folds 42 and 43. Similar gusset folds. 44 and 45, are provided between the triangular panels 40 and 4| and the end panels 3| and 32. The gusset folds 42 and 43 are connected to theend panels 3| and 32 along extensions of the fold line l4 and are connected to the triangular panels 31 and 39 along diagonal fold lines 46. and 41. The gusset fold panels 44 and 45 are connected to the end panels 3| and 32 along extensions of the fold line l5 and are connected to the triangular panels 40 and 4| along diagonal fold lines 49 and 50.

The inner surface of the carton A is coated with a thermo plastic coating which extends over the entire inner surface of the carton or at least over the inner surface of the various end flaps. This thermo plastic coating permits the sealing of the carton under heat and pressure without necessitating the intermediate application of adhesive.

As a first stage in the closure of the cartons A, these cartons are folded along the fold line l5 so that the sealing flaps I1 and 20 are superimposed and so that the thermo plastically coated surfaces thereof are in contact. The flap I1 is then sealed to the flap 20 by application of heat and pressure. This step in the production produces the folded blank best illustrated in Figure 6 of the drawings, which is supplied to the sealing mechanism illustrated in the drawings.

Thev folded carton blanks as shown in Figure 6 are fed'into the feed hopper 51 illustrated in Figures l and 2 of the drawings. The feed hopper 5 lis-shown as comprising a substantially rectangular frame having a slot 52 in one side thereof from which thecombined flaps H and I9 may project.

The feed hopper 5| supplies flat blanks to position beneath the carton expanding plunger 53 which may be of any suitable form. The expanding plunger 53 enters the flat blank and folds the same-into rectangular or tubular form and moves the carton A downwardly as indicated by the arrows in Figures 1 and 2 of the drawings.

A first step in the sealing operation may comprise the adhering of the combined glue flaps H and 2D to the exterior surface of the carton. The car-ton A is fed between the idle roller 54 and the glue applying roller 55 which supplies adhesive to the exposed surface of the sealing flap ll. The roller 55 may be supplied with adhesive in any suitable manner such as by the adhesive-supply roller 56 partially submerged in a tank or vat 51 of adhesive. When the adhesive has been applied to the sealing flap I! the carton moves downwardly before the plunger 59. The plunger 59 includes upper and lower blades 60 and side blades 6| which engage the top and bottom edges and the lateral edges of the carton to hold the same in rectangular form. The plunger '60 is moved to the right as illustrated in Figure 1 of the drawings by movement of the supporting "shaft'62 in this direction. This movement carries the carton A into a receiving pocket 63 supported upona conveyor table- 64 which is movable throughout the various stages of the sealing operation, The carton A remains in the pocket 63 on the conveyor table 64 during the entire sealing process and is not ejected from the pocket until the carton is entirely sealed.

The pocket63 includes a rear wall 65 and a air of outwardly projecting side walls 65; which extend over the side walls of the carton to hold the carton in place. Blades 61 are pivoted at the inner extremity 69 to the upper extremity of the sidewalls 65 for a purpose which will be later more completely described. Similar blades '59 are recessed in the lower surface of the pocket side walls fifi and are hinged at H to these pocket side walls. Recesses 12 in the side walls 56 allow the fingers 6!- to support the carton A during the in- 'sert-iori process-.

The plunger 59 includes a frame comprising the blades 60 and 6i and a plate 73 arranged to engage against the front surface of the carton.

This frame is slidably supported upon a pair of parallel shafts 14 connected by a connecting member I5 and secured to the plunger shaft 62.

Springs 76 are interposed between the connecting member 15 and the plunger frame 59. A folding horn H is connected to a cross member 19 secured to the ends of the shafts [4. Thus the entire plunger including the plunger frame moves in unison to insert the carton A into the pocket 63. As the carton is inserted into the pocket 63 the combined sealing flaps H and 20 are folded against the outer surface of the side wall panel l0. As the sealing flap H has previously been coated with adhesive the sealing flap l! is held by the pocket in engagement with the Wall I0 until the adhesive has set, thus adhering the sealing flaps ill and 26 to the carton side wall l0.

After the carton has been entirely inserted into the pocket 53, the folding member Tl engages the end panel 32, foldin this panel across the lower open end of the carton. This action folds the gusset panel 43 into contiguous relation with the side panel 39 and folds the gusset panel 45 into engagement with the side panel 4|, folding the carton from the position illustrated in Figure 7 of the drawings to the position shown in Figure 8 thereof. It will be noted that double thickness triangular folds are thus provided extending outwardly substantially level with the under surface of the carton and that the end panel 32 is folded into overlapping relation with the end panel 25.

With attention now to Figure 2 of the drawings, it will be noted that as the pocket 63 moved to the right as shown in this figure, with the conveyor table 64, the folded lower end of the carton is carried over the heated sealing plate 19 which is heated by any suitable means such as the heating coil all. This sealing plate 19 presses the triangular flaps at the lower end of the carton firmly together to form a tight bond therebetween. The plate l9 also presses the sealing flap 34 against the inner surface of the end panel 25 thus sealing these elements together. A relatively tight seal for the lower end of the carton is accordingly provided, but some danger of sifting might occur at the juncture between the end panel 25, the rear panel l3. and the side wall panels iii and i2, unless additional sealing steps were provided.

As the carton A is carried into the position shown at the right end of Figure 2 of the drawings, the triangular flaps are held sealed together and the sealing fiap 34 is held against the end panel 25 by means of a pressing bar or plate 8|. This plate or bar is of suflicient length to thoroughly seal the carton. Omission of this pressing plate might permit the seal to be broken after leaving the heating plate 19. While in contact with a pressing plate 8!, the thermo plastic coating cools below the softening point thereof to effect a permanent seal.

With attention now to Figure 3 of the drawings, it will be noted that after leaving the end of the pressing bar or plate 8i, the folding blades '10 are actuated to swing the triangular folds at the bottom of the carton through an angle of one hundred eighty degrees. ihe relatively stiff folds of carton stock act in knee action lever fashion on the material of the carton to crowd the material into the pin hole corners previously described. When folded to underlie the panel 32, the folds are held in place by engagement with a second pressing bar 82 which is properly slotted to permit the folding blades "it! to swing back into normal inoperative position, leaving the triangular folds in proper folded relation.

After the triangular folds have been folded inwardly as best illustrated in Figure 9 of the drawings, the next'operation of my method is to fold the end panel 25 to underlie these triangular folds. This I accomplish by any suitable means such as the folding bar 83 which engages above the panel 25 and folds this panel into the position best illustrated in Figure 10 of the drawings, In this position the lower end of the carton is thoroughly sealed except for the sealing flap 29. After the folding operation accompilshed by the folding bar 83, the carton passes over a heat sealing unit 84 heated by any suitable means such as the resistance coil 85 which acts to soften the coating of thermo plastic adhesive on the inner surface of the panel 25 and to adhere this inner surface to the under surface of the triangular folds, thereby locking these triangular folds in closed position.

From the position shown in Figure 10 of the drawings the sealing flap 29 is next folded to overlie the lower marginal edge of the outer surface of the front panel II. This is accomplished by means of a folding bar 86 which engages beneath the flange or flap 29 and presses the same against the outer surface of the panel ll. With this action the folding of the lower end of the carton is completed.

As seen in Figure 4 of the drawings, the carton A may be filled at this stage of the sealing opera-.

tion. A hopper Bl or any other suitable filling apparatus may be mounted above the cartons so as to fill the same upon completion of the sealing operation of the bottom of the carton. Either before or immediately after the filling operation the sealing flap 29 is sealed against the front panel I l by means of a heat sealing unit 89 heated by any suitable means such as the coil 90. This heat sealing unit 89 presses against the outer surface of the fiap or flange 29, pressing the same against the outer surface of the carton.

At this stage of the sealing operation it may be well to mention that while the sealing of the panel 25 at the triangular flaps, and the sealing of the flap or flange 29 to the front panel II is not as effective as the first sealing operation in which two coated surfaces were sealed together. It should be borne in mind that the only purpose in sealing the panel 25 and the flap 29 is to lock the triangular folds in folded relation. Thus a less effective seal is required than would other- I wise be necessitated.

After the carton A has been filled as by the hopper 8'! the various closing panels at the top of the carton are folded downwardly from the position shown in Figure 11 of the drawings to the position. shown in Figure 12 thereof. This I accomplish by means of a folding bar 9| which engages forwardly of the end panel SI and folds this panel over the open upper end of the carton. This operation acts to fold the triangular panels 31 and 42 into contiguous relation and simultaneously fold the triangular panels 40 and 44 into contiguous relation. I These triangular panels extend outwardly to overlie the side walls 66 of the pocket 63. The sealing flap 33 also rests upon the surface of the panel 24 as indicated in Figure 12 of the drawings. While in this position the carton passes beneath the heat sealing unit 92 which acts to seal the triangular flaps 3! and 42 together and also to seal the triangular flaps 40 and 44 together. Simultaneously the sealing flap 33 is sealed against the coated surface of the panel 24. From the heat sealing unit 92 the carton passes beneath the pressing bar 93 which holdsthe elements in sealed relation until the 7 thermo plastic material has solidified sufficiently to cause a permanent seal.

The carton is next folded from the position shown in Figure 12 of the drawings to the position shown in Figure 13 thereof. In accomplishing this result the blades 61 are caused to rotate through one hundred eighty degrees, folding the triangular folds against the end panel 3|. The triangular folds are held in folded relation by means of a pressing bar 94 which is slotted to permit the blades 61 to return to normal position.

From the position shown in Figure 13 of the drawings, the carton is next folded into the position shown in Figure 14. This is accomplished by means of a folding bar 95 which engages beneath the end panel 24 and swings the same through one hundred eighty degrees to a position overlying the triangular folds. While heldin this position the carton may pass between the heat sealing unit 96 which adheres the under surface of the panel 24 to the triangular folds. The carton is next passed beneath a pressing bar 9? which holds the panel 24 in place while the thermo plastic coating thereon solidifies. Simultaneously a folding bar 99 engages the upper surface of the sealing flap or panel 26 folding the same against the front panel H of the carton A. This flap or flange 26 may be sealed in place by means of a heat sealing unit I engaging the outer surface of the flap 26. A pressing bar or blade lfll holds the flap :26 in place after the adhesive cools, thus providing an effective seal.

It will be noted that by my process I have folded the carton from flat condition to a sealed condition as illustrated in Figure 15 of the drawings. By sealing the triangular flaps together while they are turned outwardly and subsequently turning these flaps inwardly to overlie the connected end panel, the material at the pin hole corners of the carton is crowded together to provide an effective seal. By subsequently folding the remaining end panels to overlie the triangular flaps and locking these flaps in place the material forming the carton is even more effectively crowded into the corners of the carton. As a result I provide a carton which will not sift and which will actually hold liquid for considerable periods of time if the stock of which the carton is formed is liquid proof.

In accordance with the patent statutes, I have described the principles of construction and operation of my method for sealing cartons, and while I have endeavored to set forth the best embodiments thereof, I desire to have it understood that obvious changes may be made within the scope of the following claims without departing from the spirit of my invention.

I claim:

1. The method of sealing a tubular carton having substantially rectangularly arranged side walls, end panels issuing from two opposed side walls, a sealing flap foldably connected to one end panel, and side panels issuing from the remainder of said side walls and connected to one of said first named end panels by gusset folds, the method consisting of folding said, one end panel to extend across the open end of the carton, the gusset folds overlying the side panels and the sealing flap on said one end panel lying against a portion of the inner surface of the other end panel, sealing the gusset folds to the side panels and the sealing flap of said one panel to the other end panel, holding the sealed portions until the seal is set, folding the gusset folds to overlie said one end panel, and folding the other end panel to overlie said gusset folds.

2. The method of sealing a tubular carton having substantially rectangularly arranged side walls, end panels issuing from two opposed side walls, a seal-ing flap foldably connected to one end panel, and side panels issuing from the remainder of said side walls and connected to one of said first named end panels by gusset folds, the method consisting of folding said one end panel to extend across the open end of the carton, the gusset folds overlying the side panels and the sealing flap on said one end panel lying against a portion of the inner surface of the other end panel, sealing the gusset folds to the side panels and the sealing flap of said one panel to the other end panel, holding the sealed portions until the seal is set, folding the gusset folds to overlie said one end panel, folding the other end panel to overlie said gusset folds, and fold ing the sealing flap -of said other end panel to a side wall of the carton.

3. The method of sealing a tubular carton having substantially rectangularly arranged side walls, end panels issuing from two opposed side walls, a sealing flap foldably connected to one end panel, and side panels issuing from the remainder of said side walls and connected to one of said first named end panels by gusset folds, the inner surface of said carton having a thermo plastic coating thereupon, the method consisting of folding said one end panel to overlie the open end of said carton, said gusset folds overlying said side panels with the coated surfaces thereof in contacting relation, the coated surface of the seal-ing flap of said one end panel contacting the coated surface of the other end panel, applying heat and pressure to seal said contacting surfaces together to prevent slippage therebetween, folding the gusset folds to overlie the outer surface of said one end panel, and folding said other end panel to overlie said gusset folds.

4. The method of sealing a tubular carton having substantially rectangularly arranged side walls, and panels issuing from two opposed side walls, a sealing flap foldably connected to one end panel, and side panels issuing from the remainder of said side walls and connected to one of said first named end panels by gusset folds, the inner surface of said carton having a thermo plastic coating thereupon, the method consisting of folding said one end panel to overlie the open end of said carton, said gusset folds overlying said side panels with the coated surfaces thereof in contacting relation, the coated surface of the sealing flap of said one end panel contacting the coated surface of the other end panel, applying heat and pressure to seal said contacting surfaces together to prevent slippage therebetween, folding the gusset folds to overlie the outer surface of said one end panel, and folding said other end panel to overlie said gusset folds, and folding the sealing flap on said other end panel to overlie a side wall of said carton.

5. The method of sealing a tubular carton having substantially rectangularly arranged side walls, end panels issuing from two opposed side walls, a sealing flap foldably connected to one end panel, and side panels issuing from the remainder of said side walls and connected to one of said first named end panels by gusset folds, said end panels, side panels, gusset folds and sealing flap having a coating of thermo plastic material on the inner surface thereof, the method consisting of folding said one end panel to overlie the open end of the carton, simultaneously folding the gusset folds to overlie the side panels and folding the sealing flap of said one end panel into contacting relation with the portion of the coated surface of the other end panel, sealing the contacting surfaces together to prevent slippage therebetween, folding the gusset folds to overlie said one end panel, and folding the other end panel to overlie said gusset folds.

6. The method of sealing a tubular carton having substantially rectangularly arranged side walls, end panels issuing from two opposed side walls, a sealing flap foldably connected to one end panel, and side panels issuing from the remainder of said side walls and connected to one of said first named end panels by gusset folds, said end panels, side panels, gusset folds and sealing flap having a coating of thermo plastic material on the inner surface thereof, the method consisting of folding said one end panel to overlie the open end of the carton, simultaneously folding the gusset folds to overlie the side panels and folding the sealing flap of said one end panel into contacting relation with the portion of the coated surface of the other end panel, sealing the contacting surfaces together to prevent slippage therebteween, folding the gusset folds to overlie said one end panel, folding the other end panel to overlie said gusset folds, and folding the sealing flap of said other end panel to overlie a side wall.

'2. The method of sealing a tubular carton having substantially rectangularly arranged side walls, end panels issuing from two opposed side Walls, a sealing flap foldably connected to one end panel, and side panels issuing from the remainder of said side walls and connected to one of said first named end panels by gusset folds, a coating of thermo plastic material on the inner surface of at least the end panels, side panels, gusset folds, and sealing flap of the carton, the method consisting of folding said one end panel to overlie the open end of the container, simultaneously folding the other end panel to extend outwardly from the carton at substantially ninety degrees, and folding the gusset folds to overlie the side panels and extend outwardly from the carton at substantially ninety degrees, sealing the contacting surfaces with heat and pressure to prevent slippage therebetween, folding the gusset folds to overlie said one end panel, and folding the other end panel and sealing flap of said one panel through substantially one hundred eighty degrees to overlie said gusset folds.

8. ihe method of sealing a tubular carton having substantially rectangularly arranged side walls, end panels issuing from two opposed side walls, a sealing flap foldably connected to one end panel, and side panels issuing from the remainder of said side walls and connected to one of said first named end panels by gusset folds, a coating of thermo plastic material on the inner surface of at least the end panels, side panels, gusset folds, and sealing flap of the carton, the method consisting of folding said one end panel to overlie the open end of the container, simultaneously folding the other end panel to extend outwardly from the carton at substantially ninety degrees, and folding the gusset folds to overlie the side panels and extend outwardly from the carton at substantially ninety degrees, sealing the contacting surfaces with heat and pressure to prevent slippage therebetween, folding the gusset folds to overlie said one end panel, and folding the other end panel and sealing flap of said one panel through substantially one hundred eighty degrees to overlie said gusset folds,

and folding the sealing fiap of said other end panel to overlie the side wall of the carton.

9. The method of sealing a tubular carton having substantially rectangularly arranged side walls, end panels issuing from two opposed side walls, a sealing flap foldably connected to one end panel, and side panels issuing from the remainder of said side walls and connected to one of said first named end panels by gusset folds, a coating of thermo plastic material on the inner surface of at least the end panels, side panels, gusset folds, and sealing flap of the carton, the method consisting of folding the side panels and said other end panel outwardly into substantially coplaner relationship, simultaneously folding said one end panel across the end of the carton so that the sealing flap on said one panel overlies a portion of the surface of said other end panel, and folding said gusset folds to overlie said side panels, sealing the gusset folds to the side panels and sealing the sealing flap of said one end panel to the other end panel with heat and pressure to prevent slippage between the sealed surfaces, folding the gusset folds to overlie said one end panel, folding said other end panel to overlie said gusset folds and sealing said other end panel to said gusset folds.

10. The method of sealing a tubular carton having substantially rectangularly arranged side walls, end panels issuing from two opposed side walls, a sealing flap foldably connected to one end panel, and side panels issuing from the remainder of said side walls and connected to one of said first named end panels by gusset folds, a coating of thermo plastic material on the inner surface of at least the end panels, side panels, gusset folds, and sealing flap of the carton, the method consisting of folding the side panels and said other end panel outwardly into substantially coplaner relationship, simultaneously folding said one end panel across the end of the carton so that the sealing flap on said one panel overlies a portion of the surface of said other end panel, and folding said gusset folds to overlie said side panels, sealing the gusset folds to the side panels and sealing the sealing flap of said one end panel to the other end panel with heat and pressure to prevent slippage between the sealed surfaces, folding the gusset folds to overlie said one end panel, folding said other end panel to overlie said gusset folds, sealing said other end panel to said gusset folds, folding the sealing fiap of the other end panel to overlie a portion of the side wall from which said one end panel issues, and sealing this sealing flap to the side wall with heat and pressure.

11. The method of folding a carton including four rectangularly arranged side walls having sealing flaps at each end of the blank, end panels foldably connected to two opposed side walls, second sealing fiaps foldably connected to each end panel, side panels foldably connected to the remaining side walls, and gusset folds connecting said side panels to one of said end panels, said carton having a coating of thermo plastic adhesive extending over at least a portion of the inner surface thereof, the method consisting of folding the carton blank so that said first named sealing flaps at the ends of the carton blank lie in contiguous relation, adhering said first named sealing flaps together, folding said first named sealing flaps to overlie a portion of the exterior surface of one of said side walls, and adhering said folded first named sealing flaps to said one side wall, folding said one end panel ll to overlie the end of the carton, simultaneously folding said side panels outwardly from the side walls to which they are connected, and folding said gusset folds to overlie said side panels, and simultaneously folding the second sealing flap on said one end panel into engagement with a portion of the surface of the other end panel, sealing said gusset folds firmly to the corresponding side panels and sealing said second sealing flap on said one end panel firmly to the other end panel, folding the gusset folds to overlie said one end panel, and folding the other end panel to overlie said gusset folds.

12. The method of folding a carton including four rectangularly arranged side walls having sealing flaps at each end of the blank, end panels foldably connected to two opposed side walls, second sealing flaps foldably connected to each end panel, side panels foldably connected to the remaining side walls, and gusset folds connecting said side panels to one of said end panels, said carton having a coating of thermoplastic adhesive extending over at least a portion of the inner surface thereof, the method consisting of folding the carton blank sothat said first named sealing flaps at the ends of the carton blank lie in contiguous relation, adhering said first named sealing flaps together, folding said first named seal-ing flaps tooverlie a portion of the exterior surface of one of said side walls, and adhering said folded first named sealing flaps to said one side wall, folding said one end panel to overlie the end of the carton, simultaneously folding said side panels outwardly from the side walls to which they are connected, and folding said gusset folds to overlie said side panels, and simultaneously folding the second sealing flap on said one end panel into engagement with a portion of the surface of the other and panel,

sealing said gusset folds firmly to the corresponding side panels and sealing said second sealing flap firmly on said one end panel to the other end panel, folding the gusset folds to overlie said one end panel, and folding the other end panel to overlie said gusset folds, and folding the sealing flap of said other end panel to overlie a portion of the side wall from which said one end panel issues.

13. The method of folding a carton including four rectangularly arranged side walls having sealing flaps at each end of the blank, end panels foldably connected to two opposed side walls, second sealing flaps foldably connected to each end panel, side panels foldably connected to the remaining side walls, and gusset folds connecting said side panels to one of said end panels, said carton having a coating of thermo plastic adhesive extending over at least a portion of the inner surface thereof, the method consisting of folding the carton blank so that said first named sealing fiaps at the ends of the carton blank lie in contiguous relation, adhering said first named sealing flaps together, folding said first named sealing flaps to overlie a portion of the exterior surface of one of said side walls, and adhering said folded first named sea-ling flaps to said one side wall, folding said one end panel tooverlie the end of the carton, simultaneously folding said side panels outwardly from the side walls to which they are connected, and folding said gusset folds to overlie said side panels, and simultaneously folding the second sealing fiap on said one end panel into engagement with a portion of the surface of the other end panel, sealing said gusset folds firmly to the corresponding side panels and sealing said second sealing flap firm-1y on said one end panel to the other end panel, folding the gusset folds to overlie said one and panel, folding the other end panel to overlie said gusset folds, and sealing said other end panel to said gusset folds.

14. The method of folding a carton including four rectangularly arranged side walls having sealing flaps at each end of the blank, end panels foldably connected to tWo opposed side walls, second sealing flaps foldably connected to each end panel, side panels foldably connected to the remaining side walls, and gusset folds connecting said side panels to one of said end panels, said carton having a coating of thermo plastic adhesive extending over at least a portion of the inner surface thereof, the method consisting of folding the carton blank so that said first named sealing flaps at the ends of the carton blank lie in contiguous relation, adhering said first named sealing flaps together, folding said first named sealing flaps to overlie a portion of the exterior surface of one of said side walls, and adhering said folded first named sealing flaps to said one side wall, folding said one end panel to overlie the end of the carton, simultaneously folding said side panels outwardly from the side walls to which they are connected, and folding said gusset folds to overlie said side panels, and simultaneously folding the second sealing flap on said one end panel into engagement with a portion of the surface of the other end panel, sealing said gusset folds firmly to the corresponding side panels and sealing said sealing flap firmly on. said one end panel to the other end panel, folding the gusset folds to overlie said one end panel, and folding the other end panel to overhe said gusset folds, folding the second sealing flap of said other end panel to overlie a portion of: the side wall from which said one end panel issues, sealing said other end panel to said gusset folds; and sealing said second sealing fiap on said other end panel to the side wall which it overlies.

15. In the sealing of the open end of a carton structure comprising side walls, side wall flaps hingedly connected to two opposed of said side walls, an end panel hingedly connected to another of said side walls, and end panel flaps hingedly connected to the side edges of said end panel, the steps which comprise folding the side wall flaps outwardly into coplaner relation, folding the end panel over the open end of the carton while the end panel flaps remain in the plane thereof to bring the side wall flaps and end panel flaps into face to face position; sealing said side wall flaps and said end panel flaps firmly together to form double thickness flaps extending outwardly from and substantially at right angles to, said side walls; folding the double thickness flaps onto the end panel; and sealing the double thickness flaps in the folded position over the end panel.

16. The method of sealing the open end of a carton having side walls, an end panel hingedly connected along one of its edges to one of said side walls, side wall flaps hingedly connected to the remaining side walls, and end panel flaps hingedly connected to the remaining edges of said end panel, the method which comprises folding the side wall flaps outwardly to a position substantially at right angles to said side walls, folding the end panel over the open end of the carton while the end panel flaps are in the plane thereof to bring the side Wall flaps and end panel 13 14 fiaps into face to face engagement; adhesively REFERENCES CITED securing together under pressure the end panel fla and Said side wall flaps in a position in The following references are of record in the which said end panel flaps lie coplaner with the file of h patent end panel; thereby forming double thickness flaps 5 UNITED STATES PATENTS extending outwardly, said flaps comprising two laminations secured together against slipping Number Name Date and infolding the double thickness flaps through 1973303 w Sept- 1913 an angle of approximately 180 to overlie the end 2,335,865 Lamgan et 1943 panel; and in securing the double thickness 10 flaps over the end panel.

REYNOLDS GUYER. 

